WO2023042024A1 - Foamed polylactic acid sheet, and method for producing foamed polylactic acid sheet - Google Patents
Foamed polylactic acid sheet, and method for producing foamed polylactic acid sheet Download PDFInfo
- Publication number
- WO2023042024A1 WO2023042024A1 PCT/IB2022/058244 IB2022058244W WO2023042024A1 WO 2023042024 A1 WO2023042024 A1 WO 2023042024A1 IB 2022058244 W IB2022058244 W IB 2022058244W WO 2023042024 A1 WO2023042024 A1 WO 2023042024A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- polylactic acid
- sheet
- foamed
- acid resin
- resin
- Prior art date
Links
- 229920000747 poly(lactic acid) Polymers 0.000 title claims abstract description 199
- 239000004626 polylactic acid Substances 0.000 title claims abstract description 198
- 238000004519 manufacturing process Methods 0.000 title claims description 13
- 229920005989 resin Polymers 0.000 claims abstract description 110
- 239000011347 resin Substances 0.000 claims abstract description 110
- 239000000178 monomer Substances 0.000 claims abstract description 34
- 239000010954 inorganic particle Substances 0.000 claims description 48
- 238000000034 method Methods 0.000 claims description 39
- 239000006260 foam Substances 0.000 claims description 35
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims description 28
- 238000004898 kneading Methods 0.000 claims description 27
- 238000010438 heat treatment Methods 0.000 claims description 23
- 239000003431 cross linking reagent Substances 0.000 claims description 17
- 239000011342 resin composition Substances 0.000 claims description 14
- 239000000377 silicon dioxide Substances 0.000 claims description 12
- 239000002245 particle Substances 0.000 claims description 10
- 238000001864 heat-flux differential scanning calorimetry Methods 0.000 claims description 3
- 239000012530 fluid Substances 0.000 description 41
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 description 26
- 230000008569 process Effects 0.000 description 25
- 238000004128 high performance liquid chromatography Methods 0.000 description 19
- 238000011156 evaluation Methods 0.000 description 17
- 239000000945 filler Substances 0.000 description 17
- 229910002092 carbon dioxide Inorganic materials 0.000 description 13
- 239000001569 carbon dioxide Substances 0.000 description 13
- 238000005187 foaming Methods 0.000 description 13
- 238000002844 melting Methods 0.000 description 11
- 230000008018 melting Effects 0.000 description 11
- JVTAAEKCZFNVCJ-REOHCLBHSA-N L-lactic acid Chemical compound C[C@H](O)C(O)=O JVTAAEKCZFNVCJ-REOHCLBHSA-N 0.000 description 10
- 239000000126 substance Substances 0.000 description 9
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 8
- 230000000052 comparative effect Effects 0.000 description 8
- 238000011109 contamination Methods 0.000 description 8
- 239000007788 liquid Substances 0.000 description 8
- 229920001577 copolymer Polymers 0.000 description 7
- 239000000463 material Substances 0.000 description 7
- 239000000047 product Substances 0.000 description 7
- 239000004088 foaming agent Substances 0.000 description 6
- 238000000465 moulding Methods 0.000 description 6
- 229930182843 D-Lactic acid Natural products 0.000 description 5
- JVTAAEKCZFNVCJ-UWTATZPHSA-N D-lactic acid Chemical compound C[C@@H](O)C(O)=O JVTAAEKCZFNVCJ-UWTATZPHSA-N 0.000 description 5
- 239000006087 Silane Coupling Agent Substances 0.000 description 5
- 239000011162 core material Substances 0.000 description 5
- 229940022769 d- lactic acid Drugs 0.000 description 5
- 230000007423 decrease Effects 0.000 description 5
- 238000001125 extrusion Methods 0.000 description 5
- 239000007789 gas Substances 0.000 description 5
- 238000005259 measurement Methods 0.000 description 5
- 229910052757 nitrogen Inorganic materials 0.000 description 5
- 239000008188 pellet Substances 0.000 description 5
- 238000010587 phase diagram Methods 0.000 description 5
- VTYYLEPIZMXCLO-UHFFFAOYSA-L Calcium carbonate Chemical compound [Ca+2].[O-]C([O-])=O VTYYLEPIZMXCLO-UHFFFAOYSA-L 0.000 description 4
- LCGLNKUTAGEVQW-UHFFFAOYSA-N Dimethyl ether Chemical compound COC LCGLNKUTAGEVQW-UHFFFAOYSA-N 0.000 description 4
- 239000002202 Polyethylene glycol Substances 0.000 description 4
- ATUOYWHBWRKTHZ-UHFFFAOYSA-N Propane Chemical compound CCC ATUOYWHBWRKTHZ-UHFFFAOYSA-N 0.000 description 4
- 230000000694 effects Effects 0.000 description 4
- 230000007613 environmental effect Effects 0.000 description 4
- 238000002290 gas chromatography-mass spectrometry Methods 0.000 description 4
- 229920001223 polyethylene glycol Polymers 0.000 description 4
- 239000002994 raw material Substances 0.000 description 4
- 230000003385 bacteriostatic effect Effects 0.000 description 3
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 description 3
- 238000002156 mixing Methods 0.000 description 3
- 239000000203 mixture Substances 0.000 description 3
- VLKZOEOYAKHREP-UHFFFAOYSA-N n-Hexane Chemical compound CCCCCC VLKZOEOYAKHREP-UHFFFAOYSA-N 0.000 description 3
- 229920003023 plastic Polymers 0.000 description 3
- 239000004033 plastic Substances 0.000 description 3
- 239000011164 primary particle Substances 0.000 description 3
- 238000012545 processing Methods 0.000 description 3
- ZFFMLCVRJBZUDZ-UHFFFAOYSA-N 2,3-dimethylbutane Chemical compound CC(C)C(C)C ZFFMLCVRJBZUDZ-UHFFFAOYSA-N 0.000 description 2
- 229910002012 Aerosil® Inorganic materials 0.000 description 2
- 241000894006 Bacteria Species 0.000 description 2
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 2
- RTZKZFJDLAIYFH-UHFFFAOYSA-N Diethyl ether Chemical compound CCOCC RTZKZFJDLAIYFH-UHFFFAOYSA-N 0.000 description 2
- 239000004594 Masterbatch (MB) Substances 0.000 description 2
- 238000005481 NMR spectroscopy Methods 0.000 description 2
- GQPLMRYTRLFLPF-UHFFFAOYSA-N Nitrous Oxide Chemical compound [O-][N+]#N GQPLMRYTRLFLPF-UHFFFAOYSA-N 0.000 description 2
- 229910000831 Steel Inorganic materials 0.000 description 2
- XLOMVQKBTHCTTD-UHFFFAOYSA-N Zinc monoxide Chemical compound [Zn]=O XLOMVQKBTHCTTD-UHFFFAOYSA-N 0.000 description 2
- NIXOWILDQLNWCW-UHFFFAOYSA-N acrylic acid group Chemical group C(C=C)(=O)O NIXOWILDQLNWCW-UHFFFAOYSA-N 0.000 description 2
- -1 acrylic ester compound Chemical class 0.000 description 2
- 238000004458 analytical method Methods 0.000 description 2
- ADCOVFLJGNWWNZ-UHFFFAOYSA-N antimony trioxide Chemical compound O=[Sb]O[Sb]=O ADCOVFLJGNWWNZ-UHFFFAOYSA-N 0.000 description 2
- 229910000019 calcium carbonate Inorganic materials 0.000 description 2
- NEHMKBQYUWJMIP-UHFFFAOYSA-N chloromethane Chemical compound ClC NEHMKBQYUWJMIP-UHFFFAOYSA-N 0.000 description 2
- 238000002425 crystallisation Methods 0.000 description 2
- 230000008025 crystallization Effects 0.000 description 2
- 230000003247 decreasing effect Effects 0.000 description 2
- 238000011161 development Methods 0.000 description 2
- 230000018109 developmental process Effects 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 238000000921 elemental analysis Methods 0.000 description 2
- STVZJERGLQHEKB-UHFFFAOYSA-N ethylene glycol dimethacrylate Chemical compound CC(=C)C(=O)OCCOC(=O)C(C)=C STVZJERGLQHEKB-UHFFFAOYSA-N 0.000 description 2
- 239000010439 graphite Substances 0.000 description 2
- 229910002804 graphite Inorganic materials 0.000 description 2
- FFUAGWLWBBFQJT-UHFFFAOYSA-N hexamethyldisilazane Chemical compound C[Si](C)(C)N[Si](C)(C)C FFUAGWLWBBFQJT-UHFFFAOYSA-N 0.000 description 2
- 229910052739 hydrogen Inorganic materials 0.000 description 2
- 230000007062 hydrolysis Effects 0.000 description 2
- 238000006460 hydrolysis reaction Methods 0.000 description 2
- 230000003301 hydrolyzing effect Effects 0.000 description 2
- NNPPMTNAJDCUHE-UHFFFAOYSA-N isobutane Chemical compound CC(C)C NNPPMTNAJDCUHE-UHFFFAOYSA-N 0.000 description 2
- QWTDNUCVQCZILF-UHFFFAOYSA-N isopentane Chemical compound CCC(C)C QWTDNUCVQCZILF-UHFFFAOYSA-N 0.000 description 2
- JJTUDXZGHPGLLC-UHFFFAOYSA-N lactide Chemical group CC1OC(=O)C(C)OC1=O JJTUDXZGHPGLLC-UHFFFAOYSA-N 0.000 description 2
- 239000000155 melt Substances 0.000 description 2
- 229910052751 metal Inorganic materials 0.000 description 2
- 239000002184 metal Substances 0.000 description 2
- 230000003287 optical effect Effects 0.000 description 2
- 229910052760 oxygen Inorganic materials 0.000 description 2
- 230000000704 physical effect Effects 0.000 description 2
- 229920000642 polymer Polymers 0.000 description 2
- 238000006116 polymerization reaction Methods 0.000 description 2
- 238000002360 preparation method Methods 0.000 description 2
- 239000001294 propane Substances 0.000 description 2
- 230000000630 rising effect Effects 0.000 description 2
- 239000010959 steel Substances 0.000 description 2
- 238000003756 stirring Methods 0.000 description 2
- 238000010792 warming Methods 0.000 description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 2
- QNMHRRCVEGQTPS-UHFFFAOYSA-N 1-hydroxybutyl 2-methylprop-2-enoate Chemical compound CCCC(O)OC(=O)C(C)=C QNMHRRCVEGQTPS-UHFFFAOYSA-N 0.000 description 1
- WAGRIKSHWXFXHV-UHFFFAOYSA-N 1-hydroxybutyl prop-2-enoate Chemical compound CCCC(O)OC(=O)C=C WAGRIKSHWXFXHV-UHFFFAOYSA-N 0.000 description 1
- XMTQQYYKAHVGBJ-UHFFFAOYSA-N 3-(3,4-DICHLOROPHENYL)-1,1-DIMETHYLUREA Chemical compound CN(C)C(=O)NC1=CC=C(Cl)C(Cl)=C1 XMTQQYYKAHVGBJ-UHFFFAOYSA-N 0.000 description 1
- JJTUDXZGHPGLLC-IMJSIDKUSA-N 4511-42-6 Chemical compound C[C@@H]1OC(=O)[C@H](C)OC1=O JJTUDXZGHPGLLC-IMJSIDKUSA-N 0.000 description 1
- 239000005995 Aluminium silicate Substances 0.000 description 1
- 229910052582 BN Inorganic materials 0.000 description 1
- PZNSFCLAULLKQX-UHFFFAOYSA-N Boron nitride Chemical compound N#B PZNSFCLAULLKQX-UHFFFAOYSA-N 0.000 description 1
- 229920000049 Carbon (fiber) Polymers 0.000 description 1
- 239000004215 Carbon black (E152) Substances 0.000 description 1
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 description 1
- OTMSDBZUPAUEDD-UHFFFAOYSA-N Ethane Chemical compound CC OTMSDBZUPAUEDD-UHFFFAOYSA-N 0.000 description 1
- VGGSQFUCUMXWEO-UHFFFAOYSA-N Ethene Chemical compound C=C VGGSQFUCUMXWEO-UHFFFAOYSA-N 0.000 description 1
- 239000005977 Ethylene Substances 0.000 description 1
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 1
- WOBHKFSMXKNTIM-UHFFFAOYSA-N Hydroxyethyl methacrylate Chemical compound CC(=C)C(=O)OCCO WOBHKFSMXKNTIM-UHFFFAOYSA-N 0.000 description 1
- 229910000503 Na-aluminosilicate Inorganic materials 0.000 description 1
- BPQQTUXANYXVAA-UHFFFAOYSA-N Orthosilicate Chemical compound [O-][Si]([O-])([O-])[O-] BPQQTUXANYXVAA-UHFFFAOYSA-N 0.000 description 1
- OFBQJSOFQDEBGM-UHFFFAOYSA-N Pentane Chemical compound CCCCC OFBQJSOFQDEBGM-UHFFFAOYSA-N 0.000 description 1
- BLRPTPMANUNPDV-UHFFFAOYSA-N Silane Chemical compound [SiH4] BLRPTPMANUNPDV-UHFFFAOYSA-N 0.000 description 1
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N Titan oxide Chemical compound O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 description 1
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 description 1
- DAKWPKUUDNSNPN-UHFFFAOYSA-N Trimethylolpropane triacrylate Chemical compound C=CC(=O)OCC(CC)(COC(=O)C=C)COC(=O)C=C DAKWPKUUDNSNPN-UHFFFAOYSA-N 0.000 description 1
- OKKRPWIIYQTPQF-UHFFFAOYSA-N Trimethylolpropane trimethacrylate Chemical compound CC(=C)C(=O)OCC(CC)(COC(=O)C(C)=C)COC(=O)C(C)=C OKKRPWIIYQTPQF-UHFFFAOYSA-N 0.000 description 1
- 229910021536 Zeolite Inorganic materials 0.000 description 1
- FMRLDPWIRHBCCC-UHFFFAOYSA-L Zinc carbonate Chemical compound [Zn+2].[O-]C([O-])=O FMRLDPWIRHBCCC-UHFFFAOYSA-L 0.000 description 1
- UKMBKKFLJMFCSA-UHFFFAOYSA-N [3-hydroxy-2-(2-methylprop-2-enoyloxy)propyl] 2-methylprop-2-enoate Chemical compound CC(=C)C(=O)OCC(CO)OC(=O)C(C)=C UKMBKKFLJMFCSA-UHFFFAOYSA-N 0.000 description 1
- 150000001252 acrylic acid derivatives Chemical class 0.000 description 1
- 150000001335 aliphatic alkanes Chemical class 0.000 description 1
- 229920003232 aliphatic polyester Polymers 0.000 description 1
- 239000000956 alloy Substances 0.000 description 1
- 229910045601 alloy Inorganic materials 0.000 description 1
- 125000005336 allyloxy group Chemical group 0.000 description 1
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 1
- 235000012211 aluminium silicate Nutrition 0.000 description 1
- ANBBXQWFNXMHLD-UHFFFAOYSA-N aluminum;sodium;oxygen(2-) Chemical compound [O-2].[O-2].[Na+].[Al+3] ANBBXQWFNXMHLD-UHFFFAOYSA-N 0.000 description 1
- 239000003963 antioxidant agent Substances 0.000 description 1
- 230000003078 antioxidant effect Effects 0.000 description 1
- 125000004104 aryloxy group Chemical group 0.000 description 1
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- 230000001580 bacterial effect Effects 0.000 description 1
- 238000010923 batch production Methods 0.000 description 1
- 229920006167 biodegradable resin Polymers 0.000 description 1
- 230000005540 biological transmission Effects 0.000 description 1
- 238000007664 blowing Methods 0.000 description 1
- 239000000378 calcium silicate Substances 0.000 description 1
- 229910052918 calcium silicate Inorganic materials 0.000 description 1
- OYACROKNLOSFPA-UHFFFAOYSA-N calcium;dioxido(oxo)silane Chemical compound [Ca+2].[O-][Si]([O-])=O OYACROKNLOSFPA-UHFFFAOYSA-N 0.000 description 1
- XFWJKVMFIVXPKK-UHFFFAOYSA-N calcium;oxido(oxo)alumane Chemical compound [Ca+2].[O-][Al]=O.[O-][Al]=O XFWJKVMFIVXPKK-UHFFFAOYSA-N 0.000 description 1
- 238000004364 calculation method Methods 0.000 description 1
- 239000006229 carbon black Substances 0.000 description 1
- 239000004917 carbon fiber Substances 0.000 description 1
- 229910002091 carbon monoxide Inorganic materials 0.000 description 1
- 239000000919 ceramic Substances 0.000 description 1
- HRYZWHHZPQKTII-UHFFFAOYSA-N chloroethane Chemical compound CCCl HRYZWHHZPQKTII-UHFFFAOYSA-N 0.000 description 1
- 238000004140 cleaning Methods 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 238000010924 continuous production Methods 0.000 description 1
- 239000007822 coupling agent Substances 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 125000004386 diacrylate group Chemical group 0.000 description 1
- GDVKFRBCXAPAQJ-UHFFFAOYSA-A dialuminum;hexamagnesium;carbonate;hexadecahydroxide Chemical compound [OH-].[OH-].[OH-].[OH-].[OH-].[OH-].[OH-].[OH-].[OH-].[OH-].[OH-].[OH-].[OH-].[OH-].[OH-].[OH-].[Mg+2].[Mg+2].[Mg+2].[Mg+2].[Mg+2].[Mg+2].[Al+3].[Al+3].[O-]C([O-])=O GDVKFRBCXAPAQJ-UHFFFAOYSA-A 0.000 description 1
- AFABGHUZZDYHJO-UHFFFAOYSA-N dimethyl butane Natural products CCCC(C)C AFABGHUZZDYHJO-UHFFFAOYSA-N 0.000 description 1
- HNPSIPDUKPIQMN-UHFFFAOYSA-N dioxosilane;oxo(oxoalumanyloxy)alumane Chemical compound O=[Si]=O.O=[Al]O[Al]=O HNPSIPDUKPIQMN-UHFFFAOYSA-N 0.000 description 1
- NJLLQSBAHIKGKF-UHFFFAOYSA-N dipotassium dioxido(oxo)titanium Chemical compound [K+].[K+].[O-][Ti]([O-])=O NJLLQSBAHIKGKF-UHFFFAOYSA-N 0.000 description 1
- 239000006185 dispersion Substances 0.000 description 1
- 239000005293 duran Substances 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- NKSJNEHGWDZZQF-UHFFFAOYSA-N ethenyl(trimethoxy)silane Chemical compound CO[Si](OC)(OC)C=C NKSJNEHGWDZZQF-UHFFFAOYSA-N 0.000 description 1
- 229960003750 ethyl chloride Drugs 0.000 description 1
- 239000000835 fiber Substances 0.000 description 1
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- 239000011521 glass Substances 0.000 description 1
- 239000003365 glass fiber Substances 0.000 description 1
- 230000009477 glass transition Effects 0.000 description 1
- 125000003055 glycidyl group Chemical group C(C1CO1)* 0.000 description 1
- VOZRXNHHFUQHIL-UHFFFAOYSA-N glycidyl methacrylate Chemical compound CC(=C)C(=O)OCC1CO1 VOZRXNHHFUQHIL-UHFFFAOYSA-N 0.000 description 1
- 150000008282 halocarbons Chemical class 0.000 description 1
- 239000001307 helium Substances 0.000 description 1
- 229910052734 helium Inorganic materials 0.000 description 1
- SWQJXJOGLNCZEY-UHFFFAOYSA-N helium atom Chemical compound [He] SWQJXJOGLNCZEY-UHFFFAOYSA-N 0.000 description 1
- 229920001519 homopolymer Polymers 0.000 description 1
- 229930195733 hydrocarbon Natural products 0.000 description 1
- 150000002430 hydrocarbons Chemical class 0.000 description 1
- 239000001257 hydrogen Substances 0.000 description 1
- 229910001701 hydrotalcite Inorganic materials 0.000 description 1
- 229960001545 hydrotalcite Drugs 0.000 description 1
- 230000001771 impaired effect Effects 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 230000003993 interaction Effects 0.000 description 1
- 238000000752 ionisation method Methods 0.000 description 1
- 239000001282 iso-butane Substances 0.000 description 1
- NLYAJNPCOHFWQQ-UHFFFAOYSA-N kaolin Chemical compound O.O.O=[Al]O[Si](=O)O[Si](=O)O[Al]=O NLYAJNPCOHFWQQ-UHFFFAOYSA-N 0.000 description 1
- 238000010030 laminating Methods 0.000 description 1
- 239000011344 liquid material Substances 0.000 description 1
- HCWCAKKEBCNQJP-UHFFFAOYSA-N magnesium orthosilicate Chemical compound [Mg+2].[Mg+2].[O-][Si]([O-])([O-])[O-] HCWCAKKEBCNQJP-UHFFFAOYSA-N 0.000 description 1
- 239000000395 magnesium oxide Substances 0.000 description 1
- CPLXHLVBOLITMK-UHFFFAOYSA-N magnesium oxide Inorganic materials [Mg]=O CPLXHLVBOLITMK-UHFFFAOYSA-N 0.000 description 1
- 239000000391 magnesium silicate Substances 0.000 description 1
- 229910052919 magnesium silicate Inorganic materials 0.000 description 1
- 235000019792 magnesium silicate Nutrition 0.000 description 1
- AXZKOIWUVFPNLO-UHFFFAOYSA-N magnesium;oxygen(2-) Chemical compound [O-2].[Mg+2] AXZKOIWUVFPNLO-UHFFFAOYSA-N 0.000 description 1
- 229940050176 methyl chloride Drugs 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- IJDNQMDRQITEOD-UHFFFAOYSA-N n-butane Chemical compound CCCC IJDNQMDRQITEOD-UHFFFAOYSA-N 0.000 description 1
- 229960001730 nitrous oxide Drugs 0.000 description 1
- 235000013842 nitrous oxide Nutrition 0.000 description 1
- 125000005375 organosiloxane group Chemical group 0.000 description 1
- RPQRDASANLAFCM-UHFFFAOYSA-N oxiran-2-ylmethyl prop-2-enoate Chemical compound C=CC(=O)OCC1CO1 RPQRDASANLAFCM-UHFFFAOYSA-N 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
- 239000004014 plasticizer Substances 0.000 description 1
- 239000004645 polyester resin Substances 0.000 description 1
- 229920005650 polypropylene glycol diacrylate Polymers 0.000 description 1
- 229920005651 polypropylene glycol dimethacrylate Polymers 0.000 description 1
- 239000002244 precipitate Substances 0.000 description 1
- 230000002250 progressing effect Effects 0.000 description 1
- 230000009257 reactivity Effects 0.000 description 1
- 238000004064 recycling Methods 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
- 239000013074 reference sample Substances 0.000 description 1
- 230000004044 response Effects 0.000 description 1
- 239000000523 sample Substances 0.000 description 1
- 238000001878 scanning electron micrograph Methods 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
- 229910000077 silane Inorganic materials 0.000 description 1
- 235000012239 silicon dioxide Nutrition 0.000 description 1
- 229910001388 sodium aluminate Inorganic materials 0.000 description 1
- 239000000429 sodium aluminium silicate Substances 0.000 description 1
- 235000012217 sodium aluminium silicate Nutrition 0.000 description 1
- URGAHOPLAPQHLN-UHFFFAOYSA-N sodium aluminosilicate Chemical compound [Na+].[Al+3].[O-][Si]([O-])=O.[O-][Si]([O-])=O URGAHOPLAPQHLN-UHFFFAOYSA-N 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 238000001228 spectrum Methods 0.000 description 1
- 238000000992 sputter etching Methods 0.000 description 1
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- 239000000454 talc Substances 0.000 description 1
- 229910052623 talc Inorganic materials 0.000 description 1
- 239000003017 thermal stabilizer Substances 0.000 description 1
- 229920005992 thermoplastic resin Polymers 0.000 description 1
- OGIDPMRJRNCKJF-UHFFFAOYSA-N titanium oxide Inorganic materials [Ti]=O OGIDPMRJRNCKJF-UHFFFAOYSA-N 0.000 description 1
- 125000000391 vinyl group Chemical group [H]C([*])=C([H])[H] 0.000 description 1
- 239000010456 wollastonite Substances 0.000 description 1
- 229910052882 wollastonite Inorganic materials 0.000 description 1
- 239000010457 zeolite Substances 0.000 description 1
- 239000011667 zinc carbonate Substances 0.000 description 1
- 229910000010 zinc carbonate Inorganic materials 0.000 description 1
- 235000004416 zinc carbonate Nutrition 0.000 description 1
- 239000011787 zinc oxide Substances 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
- C08J9/00—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof
- C08J9/0066—Use of inorganic compounding ingredients
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
- C08J2201/00—Foams characterised by the foaming process
- C08J2201/02—Foams characterised by the foaming process characterised by mechanical pre- or post-treatments
- C08J2201/026—Crosslinking before of after foaming
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
- C08J2201/00—Foams characterised by the foaming process
- C08J2201/02—Foams characterised by the foaming process characterised by mechanical pre- or post-treatments
- C08J2201/03—Extrusion of the foamable blend
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
- C08J2367/00—Characterised by the use of polyesters obtained by reactions forming a carboxylic ester link in the main chain; Derivatives of such polymers
- C08J2367/04—Polyesters derived from hydroxy carboxylic acids, e.g. lactones
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
- Y02W90/00—Enabling technologies or technologies with a potential or indirect contribution to greenhouse gas [GHG] emissions mitigation
- Y02W90/10—Bio-packaging, e.g. packing containers made from renewable resources or bio-plastics
Definitions
- the present disclosure relates to a foamed polylactic acid sheet, and a method for producing a foamed polylactic acid sheet.
- formed products of polylactic acid resins include oligomers and monomers and therefore have problems of growth of bacteria and the like and poor bacteriostatic properties.
- An object of the present invention is to provide a biodegradable foamed polylactic acid sheet that is hardly contaminated and excellent in environmental hygiene.
- the foamed polylactic acid sheet according to embodiments of the present invention contain a polylactic acid resin, and oligomers and monomers having molecular weights of 3,000 or less in a total amount of 1,000 ppm or less.
- Embodiments of the present invention provide a biodegradable foamed polylactic acid sheet that is hardly contaminated and excellent in environmental hygiene.
- FIG. 1 is a phase diagram illustrating a state of a substance with respect to temperature and pressure.
- FIG. 2 is a phase diagram for defining a phase range of a compressible fluid.
- FIG. 3 is a schematic diagram illustrating a continuous kneading apparatus used for producing a foam according to embodiments of the present invention.
- FIG. 4 is a schematic diagram illustrating a continuous foaming apparatus used for producing the foam according to embodiments of the present invention.
- the foamed polylactic acid sheet according to embodiments of the present invention contains a polylactic acid resin (hereinafter, also referred to as "poly lactic acid”), preferably contains a crosslinking agent, and inorganic particles, as well as, as necessary, other components.
- a total amount of oligomers and monomers having molecular weights of 3,000 or less is 1,000 ppm or less.
- the foamed polylactic acid sheet is prevented from being contaminated by bacteria to acquire excellent bacteriostatic property and food freshness keeping property.
- the polylactic acid resin is prevented from hydrolyzing by kneading the polylactic acid resin at a temperature of the polylactic acid resin being 150°C or lower, resulting in a foamed polylactic acid sheet including oligomers and monomers having molecular weights of 3,000 or less in a total amount of 1,000 ppm or less.
- a related art has had a problem that, since a poly lactic acid resin is processed at a high temperature of 190°C or higher, the polylactic acid resin hydrolyzes to contain oligomers and monomers having low molecular wights, and therefore bacterial contamination occurs and bacteriostatic property deteriorates.
- the polylactic acid resin is prevented from hydrolyzing by kneading the poly lactic acid resin at a temperature of the polylactic acid resin being 150°C or lower, resulting in a foamed polylactic acid sheet including oligomers and monomers having molecular weights of 3,000 or less in a total amount of 1,000 ppm or less.
- a content of the oligomers and monomers having molecular weights of 3,000 or less according to embodiments of the present invention can be measured e.g. using a high performance liquid chromatography (manufactured by Shimadzu Corporation) or the like.
- the measurement can be performed in accordance with the following conditions and procedures.
- polylactic acid resin may include copolymers of a D-lactic acid and an L- lactic acid, a homopolymer of either a D-lactic acid (D body) or an L-lactic acid (L body), one or a plurality of lactide ring-opened polymers selected from a group consisting of a D-lactide (D body), an L-lactide (L body), and a DL-lactide.
- D body D-lactic acid
- L body L-lactic acid
- lactide ring-opened polymers selected from a group consisting of a D-lactide (D body), an L-lactide (L body), and a DL-lactide.
- a ratio between the D-lactic acid and the L-lactic acid is not particularly limited and can be selected as appropriate depending on an intended purpose.
- the copolymer of the D- lactic acid and the L-lactic acid there is a tendency that as the lesser optical isomer decreases, a crystallinity, a melting point, and a glass transition point of the copolymer become higher. Also, there is a tendency that as the lesser optical isomer increases, the crystallinity become lower, and the copolymer becomes amorphous.
- the copolymer Since the crystallinity is associated with heat resistance of the foamed polylactic acid sheet and a forming temperature, the copolymer only needs to be used depending on an application, and the crystallinity is not particularly limited.
- the aforementioned crystallinity expresses a crystallinity degree or a crystallization speed, and the high crystallinity means either “high crystallinity degree” or “high crystallization speed”.
- the polylactic acid may be synthesized as appropriate, or a commercially available polylactic acid may be used.
- a proportion of the polylactic acid resin is preferably 95% by mass or more, more preferably 98% by mass or more, particularly preferably 99% by mass based on the foamed polylactic acid sheet.
- a polylactic acid resin proportion of less than 95% may cause a defect that other components remain even after the polylactic acid resin is biodegraded.
- the proportion of the polylactic acid is not particularly limited and can be selected as appropriate depending on an intended purpose.
- the proportion can be calculated from a ratio among materials (“material ratio”) to be compounded. If the material ratio is unknown, for example, the materials are compared with a known polylactic acid as a reference sample by the following gas chromatography mass spectrometry (GCMS) analysis, so that components of the materials can be specified.
- GCMS gas chromatography mass spectrometry
- the material ratio can also be calculated using an area ratio of spectra according to nuclear magnetic resonance (NMR) measurement and other analytical methods in combination.
- Electron Ionization (E.I.) method Detected mass range: 25 to 700 (m/z)
- the polylactic acid resin includes a crosslinking agent
- terminals of the polylactic acid resin are crosslinked with each other and terminal groups of the polylactic acid resin are blocked, so that the polylactic acid resin hardly adsorbs water.
- hydrolysis of the polylactic acid resin, and generation of monomers or oligomers having molecular weights of 3,000 or less can be suppressed.
- the molecular weight of the resin considerably increases by the addition of the crosslinking agent, a viscosity of the resin increases, resulting in a uniform and fine foam state.
- the crosslinking agent is preferably a (meth)acrylic ester compound having two or more (meth)acrylic groups in the molecule or having one or more (meth)acrylic groups and one or more glycidyl or vinyl group because of high reactivity with polylactic acid resins and little resin coloration.
- crosslinking agent may include glycidyl methacrylate, glycidyl acrylate, glycerol dimethacrylate, trimethylolpropane trimethacrylate, trimethylolpropane triacrylate, allyloxy polyethylene glycol monoacrylate, aryloxy polyethylene glycol monomethacrylate, polyethylene glycol dimethacrylate, polyethylene glycol diacrylate, polypropylene glycol dimethacrylate, polypropylene glycol diacrylate, polytetramethylene glycol dimethacrylate, and alkylene copolymers in which alkylene glycol moieties of these (meth)acrylates have different lengths, butanediol methacrylate, and butanediol acrylate.
- a proportion of the crosslinking agent is not particularly limited and can be selected as appropriate depending on an intended purpose, and is preferably 0.5% by mass or more and
- the proportion is 0.5% by mass or more, the foamed polylactic acid sheet can be prevented from being punctured, and if the proportion is 2.5% by mass or less, the foamed polylactic acid sheet is excellent in surface property and moldability.
- a difference between an endothermic amount and an exothermic amount as determined by a heat- flux differential scanning calorimetry at a heating rate of 5°C/min is 1 J/g or more and 15 J/g or less.
- the difference between an endothermic amount and an exothermic amount indicates crystallinity.
- this value is smaller than 1 J/g, the crystallinity is so small that, even when the sheet is molded into a mold shape, the sheet tries to return to the originally shape, i.e., the sheet shape, with residual heat, resulting in shrinkage without maintaining the original shape.
- the inorganic particles are blended to control sizes and an amount of bubbles of the foam, or the like.
- the inorganic particles may also serve as a foam core material.
- the inorganic particles that serve as the foam core material are also referred to as a filler in some cases.
- the inorganic particles are not particularly limited and can be selected as appropriate depending on an intended purpose.
- examples of the inorganic particles may include talc, kaolin, calcium carbonate, titanium oxide, layered silicate, zinc carbonate, wollastonite, silica, alumina, magnesium oxide, calcium silicate, sodium aluminate, calcium aluminate, sodium alumino silicate, magnesium silicate, glass balloon, carbon black, zinc oxide, antimony trioxide, zeolite, hydrotalcite, metal fiber, metal whisker, ceramic whisker, potassium titanate, boron nitride, graphite, glass fiber, and carbon fiber.
- FN202200562 is talc, kaolin, calcium carbonate, titanium oxide, layered silicate, zinc carbonate, wollastonite, silica, alumina, magnesium oxide, calcium silicate, sodium aluminate, calcium aluminate, sodium alumino silicate, magnesium silicate, glass balloon, carbon black, zinc oxide, antimony
- silica is preferable because of high affinity with a compressible fluid as described later.
- silica contains silicon dioxide represented by SiCh as a main component.
- SiCh silicon dioxide represented by SiCh
- silica particles can be broadly classified into two types: dry-processed silica and wet-processed silica. In the present disclosure, silica particles produced by both processes can be used.
- the silica is not particularly limited and can be selected as appropriate depending on an intended purpose. It is preferable that the surface of the silica is treated with a reactive compound such as a silane coupling agent, a titanate coupling agent, and an organosiloxane. Above all, the silane coupling agent is preferable because the silane coupling agent can be suitable used for surface treatment of silica particles.
- the silane coupling agent is not particularly limited and can be selected as appropriate depending on an intended purpose.
- examples of the silane coupling agent may include hexamethyldisilazane, vinyltrimethoxysilane, y-glycidoxypropyltrimethoxysilane, y- methacryloxypropyltrimethoxysilane, y-aminopropyltrimethoxysilane, and y- mercaptopropy Itrimethoxy silane .
- a number average particle diameter of the inorganic particles is not particularly limited, and can be selected as appropriate depending on an intended purpose.
- the number average particle diameter is preferably 7 nm or larger and 120 nm or smaller. If the number average particle diameter is 7 nm or larger, the inorganic particles are excellent in dispersibility, an interface between the inorganic particles and the polylactic acid is increased, and sheet properties such as an impact strength of the resultant foam are improved. If the number average particle diameter is 120 nm or smaller, a uniform and sufficiently large diameter can be obtained.
- the number average particle diameter of the inorganic particles can be expressed as Brunauer Emmett Teller (BET) specific surface area, conveniently assuming that the foam core material has a true spherical shape.
- BET Brunauer Emmett Teller
- the BET specific surface area is preferably 20 m 2 /g or larger and 5,000 m 2 /g or smaller.
- the number average particle diameter of the inorganic particles can be calculated by observing the inorganic particles (filler) in the foam by transmission electron microscope (TEM) at a magnification of 50,000 times.
- the number of the particles used for the calculation is 100.
- a proportion of the inorganic particles is not particularly limited as long as physical properties of the foamed polylactic acid sheet is not impaired, and can be selected as appropriate depending on an intended purpose.
- the proportion is preferably 0.3% by mass or more and 5.0% by mass or less based on the foamed polylactic acid sheet. If the proportion of the inorganic particles is 0.3% by mass or more, silica can effectively work as a foam core material to form a uniform and sufficiently large foam diameter. If the proportion of the inorganic particles is 5.0% by mass or less, the silica does not aggregate and is uniformly dispersed to form a uniform foam, so that physical properties of the sheet, such as impact strength of the foam can be improved.
- the proportion of the inorganic particles can be calculated from the preparation amount in producing the foam, but can also be analyzed by an inorganic elemental analysis (EA) method (O, N, H).
- EA inorganic elemental analysis
- the proportion of the inorganic particles can be quantified by a process in which the foam is put into a graphite crucible together with a flux and melted and decomposed by resistance heating in an impulse furnace in a helium stream, and oxygen is FN202200562
- WO 2023/042024 PCT/IB2022/058244 detected as carbon dioxide and hydrogen is detected as moisture by an infrared detector, and nitrogen is detected as it is by a thermal conductivity detector.
- the aforementioned other components are not particularly limited and can be selected as appropriate depending on an intended purpose.
- examples of other components may include a thermal stabilizer, an antioxidant, and a plasticizer.
- Each of these polylactic acid resins may be used alone or in combination of two or more types.
- a proportion of the other components is not particularly limited and can be selected as appropriate depending on an intended purpose. In terms of recyclability, the proportion is preferably 2% by mass or less, preferably 1% by mass or less based on the foamed polylactic acid sheet.
- the average bubble diameter of the foam in the foamed polylactic acid sheet according to embodiments of the present invention is preferably 0.01 pm or larger and 15 pm or smaller, more preferably 0.1 pm or larger and 8 pm or smaller. If the average bubble diameter is 0.01 pm or larger, the foam is not too small and the foam is excellent in flexibility. If the average bubble diameter is 15 pm or smaller, the foam is not too large and the foam is excellent in strength.
- a method for measuring the average bubble diameter of the foam is not particularly limited, and can be selected as appropriate depending on an intended purpose.
- the average bubble diameter can be measured by cross-sectioning the foamed polylactic acid sheet using an ion milling device and observing the cross-section using a scanning electron microscope (SEM). Specifically, in the obtained cross-sectional SEM image (magnification: 3,000x), gray components corresponding to the bubbles (voids) and resin components (white) FN202200562
- WO 2023/042024 PCT/IB2022/058244 are binarized using a software Image-Pro Premier (manufactured by Media Cybernetics, Inc.), an average particle diameter (Feret diameter) is determined in a range of 35 pm x 20 pm, and an average bubble diameter of the gray components (bubbles) having a Feret diameter of 0.5 pm or larger is calculated.
- a bulk density of the foam is not particularly limited and can be appropriately selected depending on an intended purpose.
- the bulk density is preferably 0.02 g/cm 3 or higher and 0.9 g/cm 3 or lower, more preferably 0.02 g/cm 3 or higher and 0.7 g/cm 3 or lower, particularly preferably 0.02 g/cm 3 or higher and 0.5 g/cm 3 or lower. If the bulk density is 0.02 g/cm 3 or higher, the foam can maintain sufficient strength. If the bulk density is 0.9 g/cm 3 or lower, the foam is excellent in flexibility and has flexible and rigid properties.
- the bulk density of the foam can be measured e.g. in accordance with JIS K 7365.
- An average thickness of the foam polylactic acid sheet according to embodiments of the present invention is not particularly limited and can be selected as appropriate depending on an intended purpose.
- the average thickness is preferably 0.001 mm or larger and 4 mm or smaller, more preferably 0.001 mm or larger and 1 mm or smaller. If the average thickness is 4 mm or smaller, moldability is improved.
- the thickness of the sheet can be decreased.
- a ratio (long side/thickness) of a length of a long side (pm) that is longer among a length in an extrusion direction (MD direction) and a length in a width direction (TD direction) of the foamed polylactic acid sheet, to an average thickness (pm) is preferably 250 or higher, more preferably 2,500 or higher. If the ratio (longer side/thickness) is 250 or higher, the sheet can be easily processed.
- the foamed polylactic acid sheet may be used as a manufactured material, or letters may be directly printed on the sheet, or the sheet may be processed using a mold to obtain a product.
- the process in which the sheet is processed using a mold to obtain a product is not particularly limited and can be selected as appropriate depending on an intended purpose.
- a conventionally-known method for a thermoplastic resin can be used, such as vacuum molding, air pressure molding, vacuum/compressed-air molding, and press molding.
- the foamed polylactic acid sheet can have at least any of a laminated layer, a coated layer, and a surface-deposited layer, on at least either a right face or a reverse face of the foamed polylactic acid sheet.
- Examples of the shape of the multilayer body obtained by the aforementioned processing on the foamed polylactic acid sheet may include a sheet shape and a bottle shape.
- a sheet-shaped multilayer body may be molded into a multilayered molded article.
- a method for preparing the sheet- shaped multilayer body is not particularly limited and can be selected as appropriate depending on an intended purpose.
- the method may include: (1) a method in which a foamed polylactic acid sheet (A) is previously prepared and a resin (B) extruded by a general melt-extruder is layered on this sheet (extrusion laminating method); and (2) a method in which two extruders are prepared, one of which extrudes a polylactic acid resin (C) to prepare a sheet, and at the same time, the other one extrudes the resin (B) (coextrusion method).
- the method for producing the foamed polylactic acid sheet according to embodiments of the present invention includes a kneading process, a foaming process, and, as necessary, other processes.
- the kneading process and the foaming process may be simultaneously or separately performed.
- the polylactic acid resin is supplied to an extruder and kneaded at a temperature of the polylactic acid resin being 150°C or lower to obtain a polylactic acid resin composition. Kneading of the polylactic acid resin at a temperature of the polylactic acid resin being 150°C or lower makes it possible to obtain a foamed polylactic acid sheet including oligomers and monomers having molecular weights of 3,000 or less in a total amount of 1,000 ppm or less.
- a foaming agent may be added in addition to the polylactic acid resin and the inorganic particles in order to promote the foaming more efficiently.
- the kneaded products of the polylactic acid resin and the inorganic particles are referred to as a polylactic acid resin composition or a masterbatch in some cases.
- the foaming agent is not particularly limited and can be selected as appropriate depending on an intended purpose.
- the foaming agent may include: a hydrocarbon e.g. a lower alkane such as propane, n-butane, isobutane, n- pentane, isopentane, and hexane; an ether such as dimethyl ether; a halogenated hydrocarbon such as methyl chloride and ethyl chloride; and a physical foaming agent e.g. a compressible gas such as carbon dioxide and nitrogen.
- the compressible gas such as carbon dioxide and nitrogen is preferable in terms of no odor, safe handling, and low environmental load.
- the compressible liquid has a property of plasticizing (softening) resins, and when rising the temperature of the compressible liquid, the resin becomes like a liquid. In this state, dispersion of the inorganic particles in the resin results in a state that the inorganic particles are dispersed in the liquid, and the inorganic particles aggregate in the liquid. Thus, it has been impossible to obtain a highly dispersed resin composition. That means, since the viscosity of the resin is unsuitable for the kneading in the presence of the compressible fluid, it has been considered that it is difficult to use a compressible liquid for kneading a resin and inorganic particles.
- the inventors intensively studied utilization of the compressible fluid for kneading the polylactic acid resin and the inorganic particles, and, as a result, it was found that, if the kneading was performed at a temperature lower than a melting point of the polylactic acid resin in the presence of the compressible fluid, the viscosity of the polylactic acid resin was suitable for the kneading, and the inorganic particles could be kneaded.
- polylactic acid resins whose melt viscosity rapidly decreases at a melting point or higher have only been kneaded in a state of a low melt viscosity so far, but in the method for producing the foamed polylactic acid sheet according to embodiments of the present invention, the inorganic particles can be kneaded in a state of high viscosity, and the compressible fluid can be directly used as the foaming agent.
- Examples of the compressible fluid may include carbon monoxide, carbon dioxide, dinitrogen monoxide, nitrogen, methane, ethane, propane, 2,3 -dimethylbutane, ethylene, and dimethyl ether.
- carbon dioxide is preferable because carbon dioxide can easily create a supercritical state owing to a critical pressure of about 7.4 MPa and a critical temperature of about 31 °C and can be easily handled owing to incombustibility.
- Each of these compressible fluids may be used alone or in combination of two or more types.
- FIG. 1 is a phase diagram illustrating a state of a substance with respect to temperature and pressure.
- FIG. 2 is a phase diagram for defining a phase range of a compressible fluid.
- the “compressible fluid” refers to a state of a substance existing in any of the regions (1), (2), or (3) illustrated in FIG. 2 in the phase diagram of FIG. 1.
- a substance existing in the region (1) is a supercritical fluid.
- the supercritical fluid refers to a fluid that exists as a noncondensable high-density fluid in a temperature/pressure region above the limit (critical point) where a gas and a liquid can coexist and that does not condense even when compressed.
- a substance existing in the region (2) is in a liquid state, which is a liquefied gas obtained by compressing a substance in a gaseous state at normal temperature (25°C) and normal pressure (1 atm).
- a substance existing in the region (3) is in a gaseous state, which is a high-pressure gas whose pressure is 1/2 (l/2Pc) or higher of the critical pressure (Pc).
- an amount of the supplied compressible fluid should be adjusted as appropriate.
- the amount of the supplied compressible fluid is preferably 2% by mass or more and 30% by mass or less. If the amount of the supplied carbon dioxide is 2% by mass or more, it is possible to prevent an undesired phenomenon of a limited plasticization effect. If the amount of the supplied carbon dioxide is 30% by mass or less, it is possible to prevent an undesired phenomenon that carbon dioxide and polylactic acid are phase- separated and a foam having a uniform thickness cannot be obtained.
- a kneading apparatus used for producing the foamed polylactic acid sheet may employ either a continuous process or a batch process. The process can be selected as appropriate depending on an efficiency of the apparatus, properties and quality of products, or the like.
- As the kneading apparatus it is possible to use single-screw extruders, twin-screw extruders, kneaders, non-screw cage-type stirring tanks, BIVOLAK manufactured by Sumitomo Heavy Industries, Ltd., N-SCR manufactured by Mitsubishi Heavy Industries, Ltd., glasses-like blades and lattice blades manufactured by Hitachi, Ltd., and tube-type polymerization tanks equipped with Kenix-type or Sulzer-type SMLX static mixer, or the like.
- self-cleaning polymerization devices such as finishers, N-SCR, and twin-screw extruders can be used. Above all, finishers and N-SCR are preferable for production efficiency, resin color tone, stability, and heat resistance.
- a compressible fluid liquid material
- Solid raw materials such as resin pellets and calcium carbonate are supplied using a quantitative feeder.
- a resin pellet and a filler as inorganic particles are mixed, and the temperature is raised.
- the heating temperature is set to be equal to or higher than the melting temperature of the resin so that the resin can be uniformly mixed with the compressible fluid in the subsequent compressible fluid supply area.
- the resin pellet is melted by warming, and the compressible fluid is supplied while the filler is in a wet state, so that the melted resin is plasticized.
- the temperature of the kneading area c is set so that the viscosity becomes suitable for kneading the filler.
- the set temperature is not particularly limited because the set temperature varies depending on the specifications of the reactor, as well as type, structure, molecular weight, etc., of the resin.
- a commercially-available polylactic acid having a weight average molecular weight (Mw) of about 200,000 is generally kneaded at a temperature 10°C to 20°C FN202200562
- the resin is kneaded at a temperature lower than the melting point of the polylactic acid, and can be kneaded with a relatively high viscosity at a temperature lower than the melting point.
- the temperature is -20°C to -80°C, more preferably -30°C to -60°C.
- the temperature only needs to be set with reference to a current value of a stirring power of the apparatus, or the like. It can be said that these set values are in a range that can be normally reached only in the present disclosure.
- the compressible fluid is removed from the polylactic acid resin composition to foam the polylactic acid resin composition.
- the compressible fluid can be removed by releasing the pressure.
- the temperature during the foaming process is preferably equal to or higher than the melting point of the polylactic acid resin.
- foaming process can be performed as follows.
- a second extruder L/D: 34, diameter: 65 mm
- a twin-screw extruder manufactured by The Japan Steel Works, Ltd.
- carbon dioxide is pressed-in from the middle of the first extruder, and the polylactic acid in which the melted inorganic particles are dispersed (filler masterbatch) and carbon dioxide as the compressible fluid are uniformly kneaded, which is cooled to a resin temperature suitable for foaming.
- the melted resin composition is extrusion-foamed from a circular die having a slit diameter of 70 mm attached to the distal end of the second extruder under a condition of a constant discharge rate (e.g. 5 to 30 kg/h) and a constant resin temperature (e.g. 100 to 200°C).
- a constant discharge rate e.g. 5 to 30 kg/h
- a constant resin temperature e.g. 100 to 200°C.
- the compressible fluid dissolved in the polylactic acid composition vaporizes and precipitates on an interface between the inorganic particles and the polylactic acid resin in response to an operation in which the solubility of the compressible fluid is changed, such as pressure reduction and warming, so that foaming occurs.
- the foaming occurs from the inorganic particles as the foam core material, and therefore, only when the inorganic particles are uniformly dispersed in the polylactic acid, a foam having uniform and fine bubbles can be produced.
- processes are not particularly limited as long as the processes can be performed for producing a conventional foamed polylactic acid sheet.
- the process can be selected as appropriate depending on an intended purpose, and examples of other processes may include a forming process in which the resin is processed into a sheet shape.
- the compressible fluid was removed from an aliphatic polyester resin composition kneaded in the extrusion forming section d with a discharge rate of 20 kg/h and a polylactic acid resin temperature of 145°C to extrusion-foam the resin composition to obtain a polylactic acid resin sheet.
- a high performance liquid chromatography (manufactured by Shimadzu Corporation) indicated that a total amount of oligomers and monomers having molecular weights of 3,000 or less was 500 ppm, and a differential scanning calorimeter (DSC) indicated that a difference between endothermic and exothermic amounts at a heating rate of 5°C/min was 7.8 mJ/mg.
- a foamed polylactic acid sheet was obtained in the same manner as in Example 1 except that the amount of the crosslinking agent in Example 1 was changed to 0.15% by mass.
- a high performance liquid chromatography (manufactured by Shimadzu Corporation) indicated that a total amount of oligomers and monomers having molecular weights of 3,000 or less was 920 ppm, and a DSC indicated that a difference between endothermic and exothermic amounts at a heating rate of 5°C/min was 5.6 mJ/mg.
- a foamed polylactic acid sheet was obtained in the same manner as in Example 1 except that the amount of the crosslinking agent in Example 1 was changed to 0.3% by mass.
- a high performance liquid chromatography manufactured by Shimadzu Corporation indicated that a total amount of FN202200562
- WO 2023/042024 PCT/IB2022/058244 oligomers and monomers having molecular weights of 3,000 or less was 800 ppm, and a DSC indicated that a difference between endothermic and exothermic amounts at a heating rate of 5°C/min was 6.5 mJ/mg.
- a foamed polylactic acid sheet was obtained in the same manner as in Example 1 except that the content of the crosslinking agent in Example 1 was changed to 2.5% by mass.
- a high performance liquid chromatography (manufactured by Shimadzu Corporation) indicated that a total amount of oligomers and monomers having molecular weights of 3,000 or less was 400 ppm, and a DSC indicated that a difference between endothermic and exothermic amounts at a heating rate of 5°C/min was 7.6 mJ/mg.
- a foamed polylactic acid sheet was obtained in the same manner as in Example 1 except that the content of the crosslinking agent in Example 1 was changed to 3.0% by mass.
- a high performance liquid chromatography (manufactured by Shimadzu Corporation) indicated that a total amount of oligomers and monomers having molecular weights of 3,000 or less was 350 ppm, and a DSC indicated that a difference between endothermic and exothermic amounts at a heating rate of 5°C/min was 8.1 mJ/mg.
- a foamed polylactic acid sheet was obtained in the same manner as in Example 1 except that the content of the filler (inorganic particles) in Example 1 was changed to 0.5% by mass.
- a high performance liquid chromatography manufactured by Shimadzu Corporation indicated that a total amount of FN202200562
- WO 2023/042024 PCT/IB2022/058244 oligomers and monomers having molecular weights of 3,000 or less was 500 ppm, and a DSC indicated that a difference between endothermic and exothermic amounts at a heating rate of 5°C/min was 1.6 mJ/mg.
- a foamed polylactic acid sheet was obtained in the same manner as in Example 1 except that the content of the filler (inorganic particles) in Example 1 was changed to 0.5% by mass.
- a high performance liquid chromatography (manufactured by Shimadzu Corporation) indicated that a total amount of oligomers and monomers having molecular weights of 3,000 or less was 550 ppm, and a DSC indicated that a difference between endothermic and exothermic amounts at a heating rate of 5°C/min was 2.4 mJ/mg.
- a foamed polylactic acid sheet was obtained in the same manner as in Example 1 except that the content of the filler (inorganic particles) in Example 1 was changed to 2.0% by mass.
- a high performance liquid chromatography (manufactured by Shimadzu Corporation) indicated that a total amount of oligomers and monomers having molecular weights of 3,000 or less was 550 ppm, and a DSC indicated that a difference between endothermic and exothermic amounts at a heating rate of 5°C/min was 13.6 mJ/mg.
- a foamed polylactic acid sheet was obtained in the same manner as in Example 1 except that the content of the filler (inorganic particles) in Example 1 was changed to 3.0% by mass.
- a high performance liquid chromatography manufactured by Shimadzu Corporation indicated that a total amount of FN202200562
- WO 2023/042024 PCT/IB2022/058244 oligomers and monomers having molecular weights of 3,000 or less was 550 ppm, and a DSC indicated that a difference between endothermic and exothermic amounts at a heating rate of 5°C/min was 14.8 mJ/mg.
- a foamed polylactic acid sheet was obtained in the same manner as in Example 1 except that the filler (inorganic particles) in Example 1 was changed to RX300 (manufactured by NIPPON AEROSIL CO., LTD., primary particle diameter: 7 nm).
- RX300 manufactured by NIPPON AEROSIL CO., LTD., primary particle diameter: 7 nm.
- a high performance liquid chromatography indicated that a total amount of oligomers and monomers having molecular weights of 3,000 or less was 400 ppm
- a DSC indicated that a difference between endothermic and exothermic amounts at a heating rate of 5°C/min was 12.3 mJ/mg.
- a foamed polylactic acid sheet was obtained in the same manner as in Example 1 except that the filler (inorganic particles) in Example 1 was changed to QSG100 (manufactured by Shin- Etsu Chemical Co., Ltd., primary particle diameter: 110 nm).
- QSG100 manufactured by Shin- Etsu Chemical Co., Ltd., primary particle diameter: 110 nm.
- a high performance liquid chromatography indicated that a total amount of oligomers and monomers having molecular weights of 3,000 or less was 650 ppm, and a DSC indicated that a difference between endothermic and exothermic amounts at a heating rate of 5°C/min was 3.8 mJ/mg.
- a foamed polylactic acid sheet was obtained in the same manner as in Example 1 except that the filler (inorganic particles) in Example 1 was changed to QSG170 (manufactured by Shin- Etsu Chemical Co., Ltd., primary particle diameter: 170 nm).
- QSG170 manufactured by Shin- Etsu Chemical Co., Ltd., primary particle diameter: 170 nm.
- WO 2023/042024 PCT/IB2022/058244 obtained polylactic acid resin sheet, a high performance liquid chromatography (manufactured by Shimadzu Corporation) indicated that a total amount of oligomers and monomers having molecular weights of 3,000 or less was 700 ppm, and a DSC indicated that a difference between endothermic and exothermic amounts at a heating rate of 5°C/min was 2.2 mJ/mg. [0072]
- a foamed polylactic acid sheet was obtained in the same manner as in Example 1 except that the foamed polylactic acid sheet extrusion-foamed from the die in Example 1 was immediately put into a cold water bath at 10°C.
- a high performance liquid chromatography (manufactured by Shimadzu Corporation) indicated that a total amount of oligomers and monomers having molecular weights of 3,000 or less was 700 ppm, and a DSC indicated that a difference between endothermic and exothermic amounts at a heating rate of 5°C/min was 0.7 mJ/mg.
- a foamed polylactic acid sheet was obtained in the same manner as in Example 1 except that the foam extrusion-foamed from the die in Example 1 was cut into an 800 mm-square sheet, this sheet was placed in a dryer at 70°C for 2 hours, then taken out and slowly cooled.
- a high performance liquid chromatography (manufactured by Shimadzu Corporation) indicated that a total amount of oligomers and monomers having molecular weights of 3,000 or less was 400 ppm, and a DSC indicated that a difference between endothermic and exothermic amounts at a heating rate of 5°C/min was 16.3 mJ/mg.
- a foamed polylactic acid sheet was obtained in the same manner as in Example 1 except that the crosslinking agent in Example 1 was changed to DURAN ATE D201 (manufactured by FN202200562
- a foamed polylactic acid sheet was obtained in the same manner as in Example 1 except that the temperature of the polylactic acid resin in Example 1 was changed to 160°C.
- a high performance liquid chromatography (manufactured by Shimadzu Corporation) indicated that a total amount of oligomers and monomers having molecular weights of 3,000 or less was 1,350 ppm, and a DSC indicated that a difference between endothermic and exothermic amounts at a heating rate of 5°C/min was 8.4 mJ/mg.
- a foamed polylactic acid sheet was obtained in the same manner as in Example 1 except that the temperature of the polylactic acid resin in Example 1 was changed to 180°C.
- a high performance liquid chromatography (manufactured by Shimadzu Corporation) indicated that a total amount of oligomers and monomers having molecular weights of 3,000 or less was 1,700 ppm, and a DSC indicated that a difference between endothermic and exothermic amounts at a heating rate of 5°C/min was 8.8 mJ/mg.
- Example 1 to 15 and Comparative Examples 1 and 2 a total amount of oligomers and monomers having molecular weights of 3,000 or less was measured using a high performance liquid chromatography (trade name: LC -20A, manufactured by Shimadzu Corporation). From the measured values, the sheet contamination was evaluated in accordance with the following evaluation criteria. Specific measurement conditions are described below. [Measurement Conditions]
- Total amount of the detected monomers and oligomers having molecular weights of 3,000 or less is less than 850 ppm
- Total amount of the detected monomers and oligomers having molecular weights of 3,000 or less is 850 ppm or more and less than 1,000 ppm
- Example 1 to 15 and Comparative Examples 1 and 2 the obtained foamed polylactic acid sheet was molded into a shallow-drawn (mold height: 22 mm) food tray using a vacuum molding machine (FLB-21, manufactured by ASANO LABORATORIES CO., LTD.), a height of the molded tray was measured, and moldability was evaluated in accordance with the following evaluation criteria.
- a vacuum molding machine FLB-21, manufactured by ASANO LABORATORIES CO., LTD.
- Container height is 21 mm or larger
- Container height is 18 mm or larger and smaller than 21 mm
- Container height is smaller than 18 mm [0082]
- a foamed polylactic acid sheet including: a polylactic acid resin; and oligomers and monomers having molecular weights of 3,000 or less in a total amount of 1,000 ppm or less.
- ⁇ 4> The foamed polylactic acid sheet according to any one of ⁇ 1> to ⁇ 3>, wherein a difference between endothermic and exothermic amounts at a heating rate of 5°C/min is 1 J/g or more and 15 J/g or less as determined by a heat-flux differential scanning calorimetry.
- ⁇ 6> The foamed polylactic acid sheet according to ⁇ 5>, wherein a number average particle diameter of the inorganic particles is 7 nm or larger and 120 nm or smaller.
- a method for producing a foamed polylactic acid sheet comprising a polylactic acid resin including: supplying the polylactic acid resin to an extruder; kneading the polylactic acid resin at a temperature of the polylactic acid resin being 150°C or lower to obtain a polylactic acid resin composition; and extruding the polylactic acid resin composition from the extruder to foam the polylactic acid resin composition.
- the foamed polylactic acid sheet according to any one of ⁇ 1> to ⁇ 7> and the method for producing the foamed polylactic acid sheet according to ⁇ 8> make it possible to solve various problems in related art and achieve the object of the present invention.
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- Health & Medical Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Medicinal Chemistry (AREA)
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- Organic Chemistry (AREA)
- Manufacture Of Porous Articles, And Recovery And Treatment Of Waste Products (AREA)
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Abstract
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Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP4713274B2 (en) | 2005-08-23 | 2011-06-29 | 積水化成品工業株式会社 | Method for producing polylactic acid resin foam |
US20200339806A1 (en) * | 2019-04-26 | 2020-10-29 | Taichi NEMOTO | Aliphatic polyester resin composition, method for producing the same, and produced product |
WO2021084800A1 (en) * | 2019-10-31 | 2021-05-06 | 株式会社Tbm | Resin composition and manufacturing method of resin molded product |
US20210163715A1 (en) * | 2019-11-28 | 2021-06-03 | Taichi NEMOTO | Method of manufacturing aliphatic polyester resin composition and product containing the aliphatic polyester resin composition |
JP2021151348A (en) | 2020-03-24 | 2021-09-30 | 株式会社三共 | Game machine |
-
2021
- 2021-09-16 JP JP2021151348A patent/JP2023043629A/en active Pending
-
2022
- 2022-09-02 WO PCT/IB2022/058244 patent/WO2023042024A1/en active Application Filing
- 2022-09-02 CN CN202280061277.8A patent/CN117940495A/en active Pending
Patent Citations (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP4713274B2 (en) | 2005-08-23 | 2011-06-29 | 積水化成品工業株式会社 | Method for producing polylactic acid resin foam |
US20200339806A1 (en) * | 2019-04-26 | 2020-10-29 | Taichi NEMOTO | Aliphatic polyester resin composition, method for producing the same, and produced product |
WO2021084800A1 (en) * | 2019-10-31 | 2021-05-06 | 株式会社Tbm | Resin composition and manufacturing method of resin molded product |
EP4052877A1 (en) * | 2019-10-31 | 2022-09-07 | TBM Co., Ltd. | Resin composition and manufacturing method of resin molded product |
US20210163715A1 (en) * | 2019-11-28 | 2021-06-03 | Taichi NEMOTO | Method of manufacturing aliphatic polyester resin composition and product containing the aliphatic polyester resin composition |
JP2021151348A (en) | 2020-03-24 | 2021-09-30 | 株式会社三共 | Game machine |
Non-Patent Citations (1)
Title |
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K. YANGR. OZISIK R: "Polymer", vol. 47, 2006, pages: 2849 |
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